On the development of a rapid method for the concentration and separation of

radiostrontium from water samples based on a modified Sr resin

Jake Surman a, Carina Dirks b, Lena Kuhne b, Steffen Happel c, Jackie Pates a and Hao Zhang a

a Lancaster Environment Centre, Lancaster University, LA1 4YQ, UKa Radiochemistry, Department of Chemistry, Philipps University Marburg ,35043 Marburg, Germany

c Triskem International, 35170 Bruz, France

Context

Rapid extraction and separation of Sr from water samples (pH5–8)

« Passive sampling »– Use in DGT (Diffusive gradients in thin-films) units– Monitoring e.g. of ground waters and wells

Rapid method– Direct load of Sr from 100 – 1000 mL– Separation on same resin/column– Batch or column approach

Modified Sr Resin

• Keep Sr Resin selectivity (crown ether), increase pH range• 1st approach: Replace 1-Octanol by HDEHP• Screening of several test resins (varying HDEHP contents)• Characterisation of best suited resin prototype• Elution studies and first tests

• pH 7• Batch experiments

• pH 7• Batch experiments

• pH 7• Batch experiments

Sr batch uptake

Application tests

• First experimentsBatch

Sr-90 spiked water sample, pH 7, 1L 1h extraction, vortex Transfert to column, separation/elution LSC measurement

Elution study (column experiment) pH7, 1 mg Sr, 100 mg Ca, 5 mg K, 0.1 mg Pb, Y, U 1L sample, 100 mL aliquots Vacuum supported separation, 5 mL/min ICP-MS measurement

Batch experiments - I 0.7 g of resin added to 1 litre of DI water spiked

with 90Sr, shaken for 1 hourSupernatant and resin separated, resin loaded

onto a columnColumn washed with 15 ml 8M HNO3 and 20 ml

2M HClFractions dried down, redissolved in 3 ml 1M

HCl and counted by LSC

Rapid method but Sr yield only 43%

Batch experiments - II 0.5 g of resin added to 1 litre of DI water spiked

with 90Sr, shaken for 1 hourSupernatant and resin separated, resin loaded

onto a column with a 0.4 g ‘guard layer’ of freshresin to lower Sr breakthrough

Column washed with 15 ml 8M HNO3 and 20 ml2M HCl

Fractions collected and counted by LSC

Sr yield improved to 73%

Column breakthrough study – direct load

2 mL column 1L water samples, pH 7, 1 mg Sr, 100 mg Ca, 5 mg K, 0.1 mg Pb, Y, U 5 mL/min 100 mL fractions Sr breakthrough starts at 600 mL For 1L sample volume Sr yield ~58% Pb fraction also contains U

2nd Option: RTILs Use of room temperature liquids (RTILs) instead of HDEHP

1-Ethyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide (EMIM)

1-Butyl-3-methylimidazoliumbis(trifluoromethylsulfonyl)imide (BMIM)

Load: 5 mL pH 7, multi-element solution

Rinse with 3x5 mL 8M HNO3, Sr elution with 4x5 mL 2M HCl Pb elution with 4x5 mL 6M HCl

Similar elution characteristics Improved purity of Pb fraction

Breakthrough experiments on-going

Additional extractants(synergistic systems)

Conclusion• On-going work• Modified Sr resinUse of HDEHP and RTILs results in extended uptake

pH range (pH 8 to high nitric acid)• Sr selectivity remains good, Sr separation possible• Very good potential for Pb separation• First batch and column tests on 1L samples

• Improvement necessary

• Discs for increased flow • DGT tests

Thank you for your attention!